Process for preparing a carrier used in olefin polymerization catalysts

Abstract

The present invention relates to a process for preparing a carrier used in olefin polymerization catalysts, comprising suspending anhydrous magnesium chloride in an inert hydrocarbon solvent and then under stirring, activating the magnesium chloride with a C2-C8 alcohol at a temperature of 30° C. to 200° C., with the molar ratio of said alcohol to said magnesium chloride being in the range of 0.05 to 2.5. Moreover, in order to make the resultant catalysts more active, the process according to the present invention can further include a pre-dispersing step conducted prior to the activation step, wherein the dispersing agent is alkoxides of titanium or C3-C8 alcohols and the molar ratio of said dispersing agent to said magnesium chloride is 0.01 to 2.0. The catalyst prepared from the resultant carrier is suitable for polymerizing ethylene or compolymerizing ethylene with alpha-olefin.

What is claimed is:  
     
       1. A process for preparing a carrier used in olefin polymerization catalysts, comprising suspending anhydrous magnesium chloride in an inert hydrocarbon solvent and then, under stirring, activating the magnesium chloride with a C 2 -C 8  alcohol at a temperature of 30° C. to 200° C., with the molar ratio of said alcohol to said magnesium chloride being in the range of 0.05 to 0.99. 
     
     
       2. The process according to  claim 1 , further comprising pre-dispersing said anhydrous magnesium chloride with a dispersing agent at a temperature of 30° C. to 200° C. prior to the activation step, wherein said dispersing agent is an alkoxide of titanium having the formula Ti(OR) 4  wherein R is a C 2 -C 6  alkyl group, or a C 3 -C 8  alcohol, and the molar ratio of said dispersing agent to said magnesium chloride is 0.01 to 2.0. 
     
     
       3. The process according to  claim 1 , wherein said C 2 -C 8  alcohol used in the activation step is selected from the group consisting of ethanol, propanol, isopropanol, butanol, hexanol, octanol and mixtures thereof. 
     
     
       4. The process according to  claim 2 , wherein said dispersing agent is selected from the group consisting of tetrabutoxy titanium, tetraethoxy titanium, and tetrapropoxy titanium. 
     
     
       5. The process according to  claim 2 , wherein said dispersing agent is selected from the group consisting of propanol, butanol, hexanol, octanol and mixtures thereof. 
     
     
       6. The process according to  claim 1 , wherein said inert hydrocarbon solvent is selected from the group consisting of C 5 -C 15  alkanes and C 6 -C 8  aromatic hydrocarbons. 
     
     
       7. The process according to  claim 6 , wherein said inert hydrocarbon solvent is selected from the group consisting of C 5 -C 12  alkanes. 
     
     
       8. The process according to  claim 1 , wherein said alcohol is added at a temperature of 60° C. to 150° C. 
     
     
       9. The process according to claims  1 , wherein said C 2 -C 8  alcohol is added at a stirring rate of 30 to 3000 rpm. 
     
     
       10. The process according to  claim 2 , wherein said dispersing agent is added at a stirring rate of 30 to 3000 rpm. 
     
     
       11. The process according to  claim 2 , wherein said dispersing agent is added at a temperature of 60° C. to 150° C. 
     
     
       12. The process according to  claim 1 , wherein said C 2 -C 8  alcohol is added to the magnesium chloride in said activating step to form a suspension containing uniform solid particles.